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.STRAGALUS TETRAPTERUS, A NEW 

POISONOUS PLANT OF UTAH 

AND NEVADA 



BY 



C. DWIGHT MARSH and A. B. CLAWSON 

Pathological Division 




UNITED STATES DEPARTMENT OF AGRICULTURE 
DEPARTMENT CIRCULAR 81 

Contribution from the Bureau of Animal Industry 
JOHN R. MOHLER. Chief 



Washington, D. C 



January, 1920 



WASHINGTON : GOVBENMBNT PRINTING OFFICE : 192a 



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ASTRAGALUS TETRAPTERUS, A NEW POISONOUS 
PLANT OF UTAH AND NEVADA. 



RESULTS OF PRELIMINARY INVESTIGATIONS. 

Late in tlie summer of 1916 the supervisor of the Dixie National 
Forest asked for an investigation of losses of cattle on a range near 
Newcastle, Utah. In a somewhat limited region, six or eight cattle 
had died in 1915 and a number were sick in 1916. The principal 
symptoms as described by local men were wealmess, " breaking down 
behind," with a weaving motion in walking, the hind feet striking 
the legs so as to wear the hair off in patches. 

In company with the supervisor and some of the local stockmen, the 
senior author made a careful examination of the range. One sick steer, 
said to be a typical case, and showing the reported symptoms, was 
found. The animal was very weak, with a rough coat, staggered as it 
walked, and exhibited peculiar weaving movements of the hind legs. 
As the owner did not wish to have it killed, no autopsy was made. 

The range where the cattle had been grazing was in the foothills, 
with nothing unusual in the vegetation except the presence of a plant 
of the pea family — an Astragalus — which at that time was new to 
the investigators. This Astragalus, which was noticeable on account 
of its peculiar pods, had been largely grazed, and at that time (Sep- 
tember) consisted mostly of dried stems. In the stomach contents of 
a steer that had died the previous year a large number of pods of the 
Astragalus were found. These facts led to the suspicion that possibly 
this plant was the cause of the trouble, as many of the leguminous 
plants are poisonous. But it was then too late to gather any of the 
plant for experimental work, and arrangements were made to obtain 
material for feeding in the succeeding summer (1917), The plants 
were not sent, however, but in 1918 and 1919 a considerable quantity 
was obtained and preliminary experiments made. 

These experiments showed conclusively that the plant is poisonous 
to cattle and sheep. Further extended experiments are necessary, 
but meantime it is thought important to report the result of the pre- 
liminary work that stockmen may be warned of the danger from the 
plant. 

153588°— Cir. 81—20 3 



4 Department Circular 81, U. S. Depf. of Agriculture. 



DESCRIPTION OF THE PLANT. 

Astragalus tctraytoms is a perennial leguminous plant belong- 
ing to the same family as the locoes, alfalfa, etc. It is from 1 to 2 
feet in height, with linear leaves, small, rather inconspicuous flowers 
of a light-f)urple color, and curved, four-winged pods. Figure 
1 shows the plant in bloom, while figure 2 shows it in pod. The 




Fig. 1. — Astragalus tetrapterus, showing the plant in flower. 

plant is readily recognized bj'^ the peculiar pods, which are unique 
in their form. Even early in the season, before the pods are formed, 
the pods of the preceding year ordinarily can be found around the 
old plants. 

The plant grows in the foothills, and so far as known now is con- 
fined to southern Utah and western Nevada, although it is possible 



Astragalus Tetrapterus, a New Poisonous Plant 5 

that further observation will show a wider range. It grows in 
scattering patches, never in such large quantities as is the case with 
some of the recognized loco plants. It is found in bloom early in 
June and generally dries up later in the summer. 




Fig. 2. — Astragalus tetrapterus, showing the form of the pods, 

EFFECT OF THE PLANT. 

The symptoms as seen in the range have already been described. 
There has not been experimental work enough to make a very com- 
plete picture of the condition produced by corral feeding. Appar- 
ently the symptoms are not especially characteristic. There is 
staggering, the weakness being more pronounced in the hind legs. 
In the case of a steer there were mild spasms, with violent expira- 



6 Department Circular 81, U. S. Dept. of Agriculture. 

tions. In a sheep, which was killed by the plant, in addition to de- 
pression and weakness, there were salivation and nausea. The 
range cases are probably due to the continued eating of rather small 
quantities, which would lead to the chronic condition described 
before. 

PRACTICAL CONSIDERATIONS. 

At this stage of the investigation no advice can be given as to the 
treatment of poisoned animals. Stockmen should recognize the fact, 
liowever, that the plant is dangerous to cattle and sheep, and prob- 
ably also to horses, and that when other forage is lacking the eating 
of the plant in large quantities may cause serious losses. If a 
heavily grazed range, where the plant is abundant, is used, it is 
reasonable to expect some losses. If animals become aflPected they 
should be removed to a location where they can get an abundance 
of feed; probably an alfalfa field would make an ideal pasture. 



POISONOUS PLANTS 

Are discussed in the following publications of the United States Department of 
Agriculture : 

PUBLICATIONS AVAILABLE FOR FREE DISTRIBUTION BY THE DEPARTMENT. 

Zygadenus, or Death Camas. (Department Bulletin 125.) 

Lupines as Poisonous Plants. (Department Bulletin 405.) 

Oak-Leaf Poisoning of Domestic Animals. (Department Bulletin 767.) 

Eradication of Ferns from Pasture Lands in Eastern United States. (Farmers' 

Bulletin 687.) 
Prevention of Losses of Live Stock from Plant Poisoning. (Farmers Bulle- 
tin 720.) 
Eradicating Tall Larkspur on Cattle Ranges in the National Forests. (Farm- 
ers' Bulletin 826.) 
Larkspur, or " Poison Weed." (Farmers' Bulletin 988.) 
The Loco-Weed Disease. (Farmers' Bulletin 1054.) 
The Cause of the " Spewing Sickness " of Sheep. (Leaflet A. 9.) 
Cicuta (Water Hemlock) as a Poisonous Plant. (Leaflet A. 15.) 
White Snakeroot or Richweed (Eupatorium urtcccfoliuni) as u Stock-Poisoning 

Plant. (Leaflet A. I. 26.) 
Eupatorium urticcefoUum as a Poisonous Plant. (Reprint from the Journal of 

Agricultural Research, A-33.) 
Notes on Larkspur Eradication on Stock Ranges. (A. I. 34.) 

PUBLICATIONS FOR SALE BY THE SUPERINTENDENT OF DOCUMENTS, GOVERN- 
MENT PRINTING OFFICE, WASHINGTON, D. C. 

Cicuta, or Water Hemlock. (Department Bulletin 69.) Price, 10 cents. 
Larkspur Poisoning of Live Stock. (Department Bulletin 365.) Price, 25 

cents. 
Stoek-Poi.<^oning Plants of the Range. (Department Bulletin 575.) Price, 50 

cents. 
Stagger Grass (Chrosperma muscsetoxicum ) as a Poisonous Plant. (Depart- 
ment Bulletin 710.) Price, 5 cents. 
The Poisonous Action of Johnson Grass. (Bureau of Plant Industry Bulletin 

90, Pt. IV.) Price, 5 cents. 
Mountain Laurel, a Poisonous Plant. (Bureau of Plant Industry Bulletin 121, 

Pt. II.) Price, 5 cents. 
The Relation of Barium to the Loco-Weed Disease. (Bureau of Plant Industry 

Bulletin 246.) Price, 10 cents. 
Menziesia, a New Stock-Poisoning Plant of the Northwestern States. (Bureau 

of Plant Industry Circular.) Price, 5 cents. . 
The Loco- Weed Disease of the Plains. (Bureau of Animal Industry Bulletin 

112.) Price, 35 cents. 
The Stock-Poisoning Plants of Montana. (Division of Botany Bulletin 26.) 

Price, 25 cents. 



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